[FFmpeg-trac] #5065(undetermined:new): A/V desync for possibly broken flv input

[FFmpeg]

#5065: A/V desync for possibly broken flv input
-------------------------------------+-------------------------------------
               Reporter:  cehoyos    |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:
                Version:  git-       |  undetermined
  master                             |               Keywords:  flv aac
             Blocked By:             |  h264
Reproduced by developer:  0          |               Blocking:
                                     |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 A user uploaded a flv sample that plays fine with ffplay but shows
 progressive A/V desync (10 seconds for the 70 second sample) when
 transcoding. The same issue can be reproduced with both {{{mplayer -ac
 ffaac}}} and {{{mplayer -ac faad}}}, vlc regularly inserts silence to keep
 A/V sync.
 {{{
 $ ffmpeg -i footy.flv -qscale 2 out.avi
 ffmpeg version N-77045-ga16243a Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      55.  9.100 / 55.  9.100
   libavcodec     57. 16.101 / 57. 16.101
   libavformat    57. 19.100 / 57. 19.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6. 20.100 /  6. 20.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
 Input #0, live_flv, from 'footy.flv':
   Metadata:
     Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
     displayWidth    : 960
     displayHeight   : 540
     fps             : 29
     profile         :
 ����������������������������������������������������������������
     level           :
 ����������������������������������������������������������������
   Duration: 00:00:00.00, start: 0.030000, bitrate: N/A
     Stream #0:0: Video: h264 (Main), yuv420p, 960x540 [SAR 1:1 DAR 16:9],
 2349 kb/s, 30.30 fps, 66.67 tbr, 1k tbn, 59.94 tbc
     Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp, 95 kb/s
 Please use -q:a or -q:v, -qscale is ambiguous
 Output #0, avi, to 'out.avi':
   Metadata:
     Server          : NGINX RTMP (github.com/arut/nginx-rtmp-module)
     displayWidth    : 960
     displayHeight   : 540
     fps             : 29
     profile         :
 ����������������������������������������������������������������
     level           :
 ����������������������������������������������������������������
     ISFT            : Lavf57.19.100
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 960x540 [SAR
 1:1 DAR 16:9], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc
     Metadata:
       encoder         : Lavc57.16.101 mpeg4
     Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, fltp,
 192 kb/s
     Metadata:
       encoder         : Lavc57.16.101 ac3
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 (native) -> mpeg4 (native))
   Stream #0:1 -> #0:1 (aac (native) -> ac3 (native))
 Press [q] to stop, [?] for help
 [avi @ 0x2118920] Non-monotonous DTS in output stream 0:1; previous: 7,
 current: 5; changing to 8. This may result in incorrect timestamps in the
 output file.
 [avi @ 0x2118920] Non-monotonous DTS in output stream 0:1; previous: 8,
 current: 6; changing to 9. This may result in incorrect timestamps in the
 output file.

 ...

 ...

 [avi @ 0x2118920] Non-monotonous DTS in output stream 0:1; previous: 194,
 current: 192; changing to 195. This may result in incorrect timestamps in
 the output file.
 [avi @ 0x2118920] Non-monotonous DTS in output stream 0:1; previous: 195,
 current: 193; changing to 196. This may result in incorrect timestamps in
 the output file.
 Past duration 0.823357 too large
 Past duration 0.725456 too large

 ...

 ...

 Past duration 0.620659 too large
 Past duration 0.803474 too large
 Past duration 0.684608 too large
 [live_flv @ 0x21143c0] Packet mismatch 0 21841
 Past duration 0.757545 too large
 frame= 1969 fps=512 q=2.0 Lsize=   57970kB time=00:01:17.44
 bitrate=6132.0kbits/s
 video:56253kB audio:1595kB subtitle:0kB other streams:0kB global
 headers:0kB muxing overhead: 0.210521%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5065>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker